1. Field of the Invention
This invention relates to lens barrels or lens mounts and, more particularly to a lens mount comprising a plurality of groups of lenses which are integrally moved in an optical-axis direction while spacing between them in the optical-axis direction is changed or modified when zoom operation is performed, and the spacing between them in the optical-axis direction is fixed when focusing operation is performed.
2. Related Art And Prior Art Statement
Hitherto, various kinds of lens mounts have been proposed in which a plurality of groups of lenses are moved upon zoom operation and upon focusing operation. For example, technical means has been proposed in Japanese Patent Laid-Open No. HEI 2-162251 (1622S1/1990) in which an angular movement tube within a lens mount is divided into two including an inner angularly moving tube and an outer angularly moving tube, the inner angularly moving tube and the outer angularly moving tube are angularly moved integrally upon zoom operation, and one of the inner angularly moving tube and the outer angularly moving tube is moved longitudinally or before and behind upon focusing operation.
However, a radial size or dimension of the lens mount increases because the angularly moving tubes are arranged as inner and outer tubes. Thus, the above-discussed technical means is not preferable for a camera in which small sizing or miniaturization has been much desired recently.
Further, hitherto, various technical means have been proposed regarding opening and closing operation of a lens barrier mechanism for a camera. For example, technical means has been disclosed in Japanese Patent Laid-Open No. SHO 64-65531 (65531/1989) in which a drive motor of an auto-focus mechanism is also used in driving of the barrier mechanism.
However, the above-discussed technical means have the following problem. That is, since a deceleration or speed-reduction gear, a drive gear and the like are arranged with a wide space left with respect to the outside of the camera, coarse particulate or dust and sand enter from the outside. The coarse particulate and the sand bite into the gears or the like so that operational failure or malfunction occurs.
Meanwhile, hitherto, various lens mounts have been proposed which are provided with a flexible printed substrate or circuit board. For example, technical means has been proposed in Japanese Utility Model Laid-Open No. SHO 61-167630 (167630/1986) in which the flexible printed circuit board is wound and is arranged between a moving lens mount and a stationary or fixed lens mount.
Moreover, technical means has been proposed in Japanese Utility Model Laid-Open No. HEI 4-2829 (2829/1992) in which a flexible printed circuit board is bent into a U-shape at a rearward portion of a moving frame, and the vicinity of the bending is pressed down by a second moving frame.
However, in the technical means proposed in Japanese Utility Model Laid-Open No. SHO 61-167630 (167630/1986), assembling ability is low because assembling is performed after a plurality of locations have been formed, and there is a fear that extrusion or protrusion is generated into an operating portion or an effective light-beam portion because there is no guide.
Furthermore, in case where the second moving frame contains or includes an optical element, proposed in Japanese Utility Model Laid-Open No. HEI 4-2829 (2829/1992), the quantity of movement with respect to the first moving frame is not determined or decided freely, and eccentricity or the like is generated by a force of the flexible printed circuit board. Thus, this causes deterioration in performance.